The Impact of Type 2 Diabetes on the Cardiovascular System in Male and Female Rats

Introduction. Type 2 diabetes mellitus is one of the main factors of the cardiovascular risk, which leads to a disproportionate increase in cardiovascular events in women and men. While the greater excess risk of diabetic vascular complications in women compared with men has been described, mechanisms underpinning the sex difference have not been identified in full. The aim of this study was to determine the impact of type 2 diabetes (T2D) on the functional state of the cardiovascular system in male and female rats. Materials and Methods. T2D was induced in male and female Wistar rats by a high-caloric diet during 14 weeks combined with intraperitoneal injections of 25 mg/kg streptozotocin twice per week. At the end of the study electrocardiograms were recorded in leads II. A comparative analysis of changes in the functional state of the heart in male and female rats with experimental T2D was conducted. Results. It was established that T2D, independently of gender, results in the formation of pathologically accelerated rhythm and sinus tachycardia in experimental animals. Experimental T2D led to the prolongation of the systole in rats of both sex and decreasing of R-wave voltage in males in comparison with control group. In addition, T2D was accompanied by multidirectional impact on the atrial function in the heart of both sexes: P wave’ amplitude was increased in females while it was decreased in males, what can indicate either right or left atrial enlargement. It was found that T2D promotes the development of myocardial diastolic dysfunction in females, in contrast to males, which was confirmed by prolongation of T-P interval and a decrease of amplitude and duration of the T wave in comparison with intact female rats. Conclusions. T2D, independently of gender, caused cardiac arrhythmias, functional changes in atrial and ventricular conduction, but only in females, in contrast to males, was accompanied by the development of myocardial diastolic dysfunction. This data justify the necessity of personalized- and gender-specific therapy development for the prevention and management of diabetic cardiovascular complications.